Device for switching between film advance and film rewind in movie projectors

ABSTRACT

A device for switching between film-advancing and film-rewinding operations of a movie projector, having a main shaft included in the film-driving means, comprises respective wheels secured to rotate with the supply reel-mounting spindle and the takeup reelmounting spindle. A support is slidably mounted between these wheels, and carries a pair of pulleys rotatably mounted at respective opposite ends thereof and each adjacent a respective wheel. A drive pulley is mounted on the main shaft for rotation therewith, and an endless belt is trained around the drive pulley and the two pulleys on the support. The direction of tension in the belt changes in accordance with the direction of rotation of the main shaft, to shift the support in the direction of the tension to effect driving of a respective spindle wheel by the belt through rotation of the adjacent pulley. A reversing wheel is rotatably mounted between one spindle wheel and its associated pulley. Either the takeup reel or the supply reel is selected automatically for driving in response to the direction of rotation of the main shaft.

United States Patent Kadowaki [54] DEVICE FOR SWITCHING BETWEEN FILMADVANCE AND FILM REWIND IN MOVIE PROJECTORS [72] Inventor: TatsusukeKadowaki, Yokohama, Japan [73] Assignee: Kabushiki Kaisha Ricoh, Tokyo,Japan [22] Filed: Sept. 10, 1970 [21] Appl.No.: 70,696

1 Feb. 22, 1972 3,159,841 12/1964 Castedelloetal. ..352/l04 3,527,4279/1970 ODonnell ..242/205 Primary Examiner-Leonard D. ChristianAttorney-McGlew and Toren [5 7] ABSTRACT A device for switching betweenfilm-advancing and film-rewinding operations of a movie projector,having a main shaft included in the film-driving means, comprisesrespective wheels secured to rotate with the supply reel-mountingspindle and the takeup reel-mounting spindle. A support is slidablymounted between these wheels, and carries a pair of pulleys rotatablymounted at respective opposite ends thereof and each adjacent arespective wheel. A drive pulley is mounted on the main shaft forrotation therewith, and an endless belt is trained around the drivepulley and the two pulleys on the support. The direction of tension inthe belt changes in accordance with the direction of rotation of themain shaft, to shift the support in the direction of the tension toeffect driving of a respective spindle wheel by the belt throughrotation of the adjacent pulley. A reversing wheel is rotatably mountedbetween one spindle wheel and its associated pulley. Either the takeupreel or the supply reel is selected automatically for driving inresponse to the direction of rotation of the main shaft.

8 Claims, 3 Drawing Figures PATENTEDFB22 I972 SHEET 1 [IF 2 .1 mum INVENTOR.

TATSUSUKE KADOWARI my/mm! 7m ATTORNEYS PAIENTEOrEa22 m2 3. 643 .896

SHEET 2 [IF 2 INVENTORQ TATSUSUKF. KADOWAKI mfawmam ATTORN BACKGROUND OFTHE INVENTION It is already known to move a film in a direction oppositeto the normal direction of movement, when the film is screened by aprojector, so as to provide a comical effect of .the projected image. Onthe other hand, it is necessary to rewind the film from the takeup reelonto the supply reel in order to be ready for the next screening whenprojection of a film has been completed. I

For this purpose, it has hithertobeen customary to use a clutchmechanism, in conventional movie projectors, for moving an intermediategear or an intermediate friction wheel so as to render one of the filmsupply reel and .film talteup reel operative and the other inoperative.Rotation ,direction control means, such as a triangular annular clutch,for example, for regulating the direction of rotation of the film supplyreel, when the film is advanced, and for regulating the direction ofrotation of the film takeup reel, when the film is to be rewound, havebeen necessary. Known arrangements require a multiplicity of separatecomponents which inevitably complicate the structure and make itdifficult,-if not impossible, to reduce the overall size of amovie-projector to a compact size.

SUMMARY OF THE INVENTION This invention relates to movie projectors and,more particularly, to a novel, simplified for improved device whereswitching between film-advancing and film-rewinding operations.

In accordance with the invention, he change in the direction of tensionof a belt for transmitting rotation of the main shaft to rotation ofreel drive means, which change in tension direction takes placeresponsive to change in the direction of rotation of the main shaft, isutilized to effect automatic switching of the reel driving fromthepickup reel to the supply reel, or vice versa.

More specifically, each of the two reel-mounting. spindles is providedwith a respective wheel rotatable therewith. A support is slidablymounted between thetow wheels. and carries a pair of pulleys rotatablymounted thereon at respective opposite ends thereof, each pulley beingadjacent a respective spindle wheel. A drive pulley is mounted on themain shaft for rotation therewith, and an endless belt is trained aroundthe three pulleys so that all three pulleys are driven from the mainshaft. The direction of tension in the endless belt, which changes inaccordance with the direction of rotation of the main shaft, shifts thesupport in the direction of tension to effect driving of a respectivespindle wheel by the belt through rotation of the adjacent respectivepulley. Preferably, a rotatable reversing wheel is interposed betweenone spindle wheel and the associated pulley on the support.

An object of the invention is to provide an improved and simplifieddevicefor switching automatically between film-advancing andfilm-winding operations in a movie projector.

Another object is to provide such a device which is simple andinexpensive in construction, comprises relatively few components, and isadapted to mass-production techniques.

A further object of the invention is to provide such a device whichoperates automatically responsive to change in the direction of rotationof a main shaft forming part of the filmdriving mechanism.

Another object of the invention is to provide such a device in which thespindle wheels may be driven either frictionally or through intermeshinggears.

A further object of the inventionis to provide such a device which doesnot require any special means to regulate or select the direction ofrotation of thefilmsupply reel spindle or the takeup reel spindle.

For an understanding of the principles of the invention, reference ismade to the following description of a typical embodiment thereof asillustratedjn the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a side elevation view of a movie projector embodying theinvention;

FIG. 2 is a side elevation view of one embodiment of switching device inaccordance with the invention, illustrating the device in the state inwhich film is rewound from the takeup reel to the supply reel; and

FIG. 3 is a view similar to FIG. 2 but illustrating the device in thestate in which it has been switched from the film-rewinding operation tothe film-advancing operation.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, afilm-supply reel-mounting spindle 2, for mounting a supply reel 1 formovie film, is rotatably mounted on a sidewall of a projector 3, and awheel 4 is formed integrally or secured fixedly to spindle 2 at theinner end of the latter. A movie film 5, paid out from supply reel 1, isguided by a guide wheel 7 disposed above a projection lens 6 to form aloop8, and is moved along the rear end of projection lens 6 to formaloop 9. Thereafter, film 5 is guided by guide wheels 10, 11 and 12 andwound up on a film takeup reel 13. The illustrated path of movement ofthe film is similar to that in conventional movie projectors.

Takeup reel 13 is mounted on a takeup reel-supporting spindle 14rotatably mounted on the same sidewall of projector 3 as that on whichsupply reel-mounting spindle 2 is rotatably mounted. Like spindle 2,spindle 14 has a wheel 15 formed integrally therewith, or fixedlysecured thereto, and disposed at its inner end.

A pulley support 16 is arranged between wheels 4 and I5 and rotatablysupports, through shafts, a pulley 17, at its forward end 16a, and apulley 18, at its rearward end 16b. Pulley support 16 is suitablymounted for reciprocation longitudinally of the projector on thesidewall of the projector supporting the spindles 2 and 14, as byloosely receiving, in slots 21 and 22 formed in support 16, respectiverivets 19 and 20 secured to the inner surface of the projector sidewall.

Pulleys 23 and 24, arranged for rotation in a plane extendinglongitudinally of the projector, are rotatably mounted below support 16,and are supported by respective shafts 25 and 26 secured to the innersurface of the aforementioned sidewall of projector 3. A pulley 28 issecured to a main shaft 27 of projector 3, and which shaft includes ashutter plate (not shown) mounted at its forward end in the same manneras in conventional movie projectors. An endless belt 29, trained aboutpulley 28 as if pulley 28 were hung from the endless belt, is alsotrained about pulleys 23, 17, 18 and 24.

Main shaft 27 is adapted to rotate in the direction of the arrow A inFIG. 2 when the film is moved in a normal direction, or advanced, forscreening, and is rotated in the direction of the arrow D of FIG. 3,when the film is moved in a reverse or rewind direction for eitherscreening or rewinding. An intermediate roller 30 is arranged betweenrearmost pulley l8 and wheel 15, and is rotatably supported by a shaft33 on the free end of an arm 32 pivotally supported at its based end bya shaft 31 attached to the inner surface of the above-mentioned sidewallof projector 3. Roller 30 acts as a reversing roller between pulley 18and wheel 15.

Wheel 4, pulleys 17 and 18, intermediate roller 30 and wheel 15 aredisposed in the same vertical plane. As illustrated in FIGS. 1 and 2,that portion of endless belt 12 which is maintained in intimate contactwith the forward portion of the circumference of pulley 17 is broughtinto contact with wheel 4, through an intermediate roller 34,,whensupport 16 has moved forwardly. Similarly, that portion of endless belt29 which is maintained in intimate contact with the rearwardportion ofthe circumference of pulley 18 is brought into contact with wheel 15through intermediate roller 30 when pulley support 16 is movedrearwardly.

The switching device operates in a manner which will now be described.If main shaft 27 is rotated in the direction of arrow A of FIG. 2, or inthe direction in which the film is advanced or moved in its normaldirection during screening, when the switching device is in the stateshown in FIG. 2, then belt 29 moves in the direction of arrow B. Pulley17 is moved rearwardly, or to the right as viewed in FIG. 2, by thetension of belt 29 exerted between drive pulley 28 and pulley 17. Therearward movement of pulley 17 causes support 16 to move rearwardly, ina sliding motion as guided by rivets 19 and 20, into the position shownin FIG. 3. As support 16 moves rearwardly, the portion of belt 29maintained in contact with the rearward portion of the circumference ofpulley 18 moves intermediate roller 30 into pressing engagement withwheel 15. Accordingly, wheel is rotated, through intermediate roller 30,in the direction of the arrow C, of FIG. 3 by belt 29 moving in thedirection of the arrow B. Film takeup reel 13 (FIG. 1), which is fixedto rotate with wheel 15, is rotated in the direction of arrow C. Withthe switching device in this state, belt 29 is released from engagementwith wheel 4 and no longer rotates this wheel, film supply reel 1 thusrotating in an idling motion.

As the film advancing operation progresses, the diameter of the roll offilm formed on the film takeup reelincreases. Since, however, the rateof movement of the film is constant, it is necessary to reduce the rateor rotation of the film takeup reel as the diameter of the roll of filmformed thereon increases. In conventional movie projectors, it hashitherto been customary to frictionally connect the takeup reel spindleto the drive means for causing a slip to occur between these components.

In movie projectors embodying the present invention, takeup reel spindle14 may be frictionally connected to wheel 15 by suitable means. Inaccordance with the present invention, frictional connection ismaintained between wheel 15 and intermediate roller 30, or betweenintermediate roller 30 and belt 29, even if wheel 15 and spindle 14 areformed completely integral with each other. This eliminates the need toprovide special means for frictionally connecting the takeup reelspindle to the drive means.

If main shaft 27 is rotated in the direction of arrow D in FIG. 3, forscreening the film in the reverse direction or for rewinding the film,belt 29 moves in a direction opposite to that indicated by arrow B. Thiscauses support 16 to move forwardly, or to the left, from the positionshown in FIG. 3 into the position shown in FIG. 2, by virtue of thetension of belt 29 moving between the drive pulley 28 and pulley 18.When support 16 is in the position shown in FIG. 2, that portion of belt29 engage with the forward portion of circumference of pulley 17 pressesthrough intermediate roller 34, against wheel 4 to rotate wheel 4clockwise. This causes film supply reel 1 (FIG. 1) to rotate in thedirection of the arrow shown in FIG. 1, for rewinding the filmthereon'from the film takeup reel 13 which now rotates in an idlingmotion.

While the film-supply reel-supporting spindle 2 and the film takeupreel-supporting spindle 14 have been described as being driven byfrictional transmission of rotation, .it will be understood that a gearmay be formed integral with, or fixed to, each of thepulleys 17 and 18,spindle 2 and spindle 14, so that the two reel spindles 2 and 14 can berotated by a gear transmission of rotation while regulating the extentof sliding movement of support 16. Furthermore, pulleys 23 and 24 may beomitted or their positions may be changed as desired, de-

pending on the direction of rotation of spindle 2 and spindle From theforegoing description, it will be appreciated that, in the presentinvention, pulleys, for transmitting the rotation of the main shaft bymeans of an endless belt, are movably supported by a support movablelongitudinally of the movie projector, and which support is movedbackwardly and forwardlyby utilizing a change in thedirection of tensionof the belt caused by a change in the direction of rotation of the mainshaft. Thereby, the film reel spindles can be selectively adapted forrotation either to advance the film or to rewind supporting spindle,since the supply reel-supporting spindle is allowed to rotate idly whenthe main shaft rotates in a normal direction and the film takeup reelsupport spindle is permitted to rotate idly when the main shaft rotatesin a reverse direction. The switching device in accordance with theinvention is simple in construction and positive in operation, and canbe produced at low cost by mass-production techniques.

While a specific embodiment of the invention has been shown anddescribed in detail to illustrate'the application of I the principles ofthe invention, it will be understood that the invention may be embodiedotherwise without departing from such principles.

What is claimed is:

1. In a movie projector having a film-supply reel-mounting spindle, afilm takeup reel-mounting spindle, and film-driving means including arotatable main shaft, a device for switching between film-advancing andfilm-rewinding operations comprising, in combination, respective firstwheels secured to rotate with said spindles to rotate respectivereelsmounted thereon; a support slidably mounted between said firstwheels for reciprocation relative thereto; a pair of second wheelsrotatably mounted on said support at respective opposite ends thereof,each adjacent a respective first wheel; a drive pulley mounted on saidmain shaft for rotation therewith; and an endless belt trained around.said drive pulley, extending toward opposite ends of said support, andin'driving relation with both said second wheels; the direction oftension in said endless belt being changed in accordance with thedirection of rotation of said main shaft to shift said support in thedirection of the tension to effect driving of a respective first wheelby said belt through rotation of the adjacent respective second wheel. I

2. In a movie projector, a switching device as claimed in claim 1, inwhich said second wheels are pulleys having said endless belt trainedtherearound; selective driving of a respective first wheel beingeffected by frictional engagement between the selected first wheel andthat portion of said endless belt trained around the adjacent pulley.

3. In a movie projector, a switching device as claimed in claim 1,including a rotation direction-reversing third wheel interposed betweenone of said first wheels and the adjacent second wheel.

4. In a movie projector, a switching device as claimed in claim 3, inwhich said third wheel is interposed between the first wheel secured tosaid takeup reel-mounting spindle and the adjacent second wheel.

5. In a movie projector, a switching device as claimed in claim 4, inwhich said third wheel is rotatably mounted at the free end of apivotally supported arm and is continuously driven by said belt throughrotation of the adjacent respective second wheel.

6. In a movie projector, a switching device as claimed in claim 2, inwhich said support is an elongated slide mounted on said projectorthrough the medium of a pair of elongated slots in said slide havingengaged therein respective pin members on said projector.

7. In a movie projector, a switching device as claimed in claim 2, inwhich said main shaft extends parallel to the direction of reciprocationof said support; and a pair of intermediate pulleys each interposedbetween said drive pulley and a respective pulley on said support, andhaving said endless belt trained therearound.

8. In a movie projector, a switching device as claimed in claim 1, inwhich all of said first and second wheels are rotatable in a commonplane.

1. In a movie projector having a film-supply reel-mounting spindle, afilm takeup reel-mounting spindle, and film-driving means including arotatable main shaft, a device for switching between film-advancing andfilm-rewinding operations comprising, in combination, respective firstwheels secured to rotate with said spindles to rotate respective reelsmounted thereon; a support slidably mounted between said first wheelsfor reciprocation relative thereto; a pair of second wheels rotatablymounted on said support at respective opposite ends thereof, eachadjacent a respective first wheel; a drive pulley mounted on said mainshaft for rotation therewith; and an endless belt trained around saiddrive pulley, extending toward opposite ends of said support, and indriving relation with both said second wheels; the direction of tensionin said endless belt being changed in accordance with the direction ofrotation of said main shaft to shift said support in the direction ofthe tension to effect driving of a respective first wheel by said beltthrough rotation of the adjacent respective second wheel.
 2. In a movieprojector, a switching device as claimed in claim 1, in which saidsecond wheels are pulleys having said endless belt trained therearound;selective driving of a respective first wheel being effected byfrictional engagement between the selected first wheel and that portionof said endless belt trained around the adjacent pulley.
 3. In a movieprojector, a switching device as claimed in claim 1, including arotation direction-reversing third wheel interposed between one of saidfirst wheels and the adjacent second wheel.
 4. In a movie projector, aswitching device as claimed in claim 3, in which said third wheel isinterposed between the first wheel secured to said takeup reel-mountingspindle and the adjacent second wheel.
 5. In a movie projector, aswitching device as claimed in claim 4, in which said third wheel isrotatably mounted at the free end of a pivotally supported arm and iscontinuously driven by said belt through rotation of the adjacentrespective second wheel.
 6. In a movie projector, a switching device asclaimed in claim 2, in which said support is an elongated slide mountedon said projector through the medium of a pair of elongated slots insaid slide having engaged therein respective pin members on saidprojector.
 7. In a movie projector, a switching device as claimed inclaim 2, in which said main shaft extends parallel to the direction ofreciprocation of said support; and a pair of intermediate pulleys eachinterposed between said drive pulley and a respective pulley on saidsupport, and having said endless belt trained therearound.
 8. In a movieprojector, a switching device as claimed in claim 1, in which all ofsaid first and second wheels are rotatable in a common plane.